Aerobic rice perspectives in India: progress and challenges

Abstract

Rice is a semi-aquatic plant and it grows well under lowland flooded anaerobic conditions. The increasing scarcity of water has threatened the sustainability of the irrigated rice production system and hence the food security and livelihood of rice farmers. With the looming problem of water scarcity, farmers and researchers are looking for alternatives to reduce water use in rice production without compromising yield. Aerobic rice is a new production system in which rice is grown in nonpuddled, nonflooded soil with the use of external inputs such as supplementary irrigation and fertilizer with the aim to obtain high yield. The savings in labor input has further changed the perceptions of people toward adopting aerobic rice. Its adoption is facilitated by the availability of efficient herbicides for weed control and suitable rice varieties for aerobic conditions. Yield obtained with aerobic rice varieties varied from 3.5 to 6.0 t ha−1, which is almost double that obtained with upland rainfed varieties, and 25% to 30% less than that obtained with irrigated lowland varieties grown under flooded conditions. A yield decline under aerobic conditions was observed when aerobic rice was continuously grown and the decline was greater in the dry season than in the wet season. To improve aerobic rice yield, the focus should be on combining the drought-tolerance characteristics of upland varieties with the high yield of lowland varieties and growth-limiting factors such as increased availability of N, P, Zn, and Fe; efficient weed control measures; and tolerance of root-knot nematodes. At the Central Rice Research Institute (CRRI), Cuttack, the research carried out under the Asian Development Bank-supported project “Developing and disseminating water-saving rice technologies in South Asia” led to the release of two high-yielding aerobic varieties, CR Dhan 200 and Anagha, for cultivation by farmers, and 27 aerobic rice lines are being tested in the All India Coordinated Rice Improvement Project (AICRIP). Some of these lines are likely to be released in the future as aerobic rice varieties for cultivation in different water-short areas